Early Radar Slip Rings

From Rutgers Oral History Archives.

Jared Kosch: This begins an interview with Robert H. Zeliff, Class of 1943, on May 17, 2003.

[Much material skipped.]

JK: What were your feelings on being involved in radar in its early days and its use in World War II? Can you give me a little background as to how radar came into being in this time and its significance, possibly, in the attack on Pearl Harbor, as well as its significance generally throughout the war?

RZ: No, I’m hardly an expert on that, but the radar really, in its practical infancy, was developed in England, and all of our people that got into radar, in their early training, had to go to England to get it, because that’s where the knowledge was. So, what we picked up to get our radar program starting just grew out of the development that was really going on in England. … To my knowledge, the first two radars that were developed that were put into, you know, mass use by our forces were the SCR-268 and the SCR-270. SCR, incidentally, it was “Signal Corps Radio;” they didn’t even have a name for it, and so, … they had numbers, just like a radio did, but it was [radar]. … The 268 was a searchlight-control radar, because that was the first application, was to try to help to steer searchlights, and the SCR-270 was the first long-range search radar and that was the one that was employed in Oahu at the time of Pearl Harbor, but, again, this was such a new device that the “old guard” officer corps had no real confidence in it at all and they just thought it was a new toy that they were playing with, I think. I think that’s pretty much the story. I’m not, of course, conversant on anything first-hand, but … there’s no question about it, that the radar was active that morning and did pick up the Japanese flight coming in, but, essentially, what it amounts to is, they couldn’t get anybody to believe that, you know, what it could possibly have been, and, again, I guess, because nobody had really understood, you know, the tactical significance of this new toy. Of course, the things quickly changed and, like everything else, the radar program blossomed very quickly after, after World War II [developed] and special radars were developed for the Navy, which were different than the ones that developed for the Army. I’d mentioned the SCR-584, which is the other one I was trained on and did some instructing [on]. Now, that was a radar that was used for gun laying, for directing fire of antiaircraft artillery. … 584 was used extensively during the war and was used for, I’ve seen them in the field in other countries, because we gave some of them, I think, to the Russians and, somehow or another, some of them got in Chinese hands, and I think I’ve seen them used, like, thirty, forty years after the war was over. It was a very successful radar. It was ten-centimeter radar, shortwave radar, that had a long life, yes, and, as I say, radar today, I would hesitate even to talk about it, because it has advanced way beyond any experience I had with it. So, it’s not the same animal, but a derivative from the same technology. I mean, you can see that, you know, if you follow the development of radar, how it was an evolutionary process and started out from one common base. Interesting little story about this; the English developed [a system that] had their radars where the operator would sit on the pedestal that the antenna was on. So, if it was an antenna that was a rotating antenna, … to track aircraft, the operating hood, that would rotate around with the antenna. … When we first started to develop our rotating ones, we had, we called it “slip rings,” where we could make electrical contact with the radar, but with the operator staying fixed. … Again, the English were one of the first ones that developed automatic tracking radars, where you could lock on to a target and, without the operator doing anything, … you could get it to follow the radar, I mean, the radar to follow, track, the target, but, in the early ones they developed over there, and, of course, they had the same business where they would go around with the antenna; … they started off, they put one of their first prototypes in Hyde Park in London. …

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RZ: When they first picked up a flight of incoming [aircraft], a German flight, they’d be about a hundred miles out and, at that distance, a group of planes just looked like one target, but, as they got closer, then, you could start to see the individual airplanes would start to show up on the screen. … Of course, this device, attempting to lock on a target, couldn’t figure out which one, when they start [breaking up], one started to become many, which one to lock on. So, these [radar], this antenna would bounce around [laughter] and the operators in it would be bouncing around, they’d be flying off the walls, until they figured out, … for that, they had to figure out a little different way [of] how to handle that problem. I think that probably [is] what got the development of the slip rings going, I guess, [laughter] when they started bouncing operators off the wall … on these automatic tracking radars, but, oh, I would venture to say there are probably a thousand stories, you know, semi-comical, … in the early days of many inventions, as that one always, always made me laugh.